ll /proc/pid/exe

ps x|grep nginx

20820 ? Ss 0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf 20849 pts/4 S+ 0:00 grep nginx

ll /proc/20820/exe

lrwxrwxrwx 1 root root 0 08-26 15:19 /proc/20820/exe -> /usr/local/nginx/sbin/nginx